Validating mercury levels in catfish Netuma thalassina (Rüppell, 1837) during and aftermath ‘fish kill’ in Kuwait Bay

Abstract

Mass mortality of Catfish Netuma thalassina during the peak summer in Kuwait Bay prompted the study of mercury concentrations using direct mercury analyzer (DMA-80) during the ‘fish kill’ otherwise, found below the detectable limits. The mean mercury (Hg) concentrations in seawater, sediment and body parts of N. thalassina (0.27 ng L-1, 0.35 ng g-1, 0.23 ng g-1) was high during ‘fish kill’ on 29th April, 2017 when compared aftermath the ‘fish kill’ (0.20 ng L-1, 0.29 ng g-1 and 0.15 ng g-1) respectively. Hg concentrations in the collected samples were observed in the sequence of Site-II>Site-I>Site-III. Fish stress was validated by hepatosomatic index (HSI). During ‘fish kill’ a decrease in liver weight due to liver shrinkage against their body weight was observed in contrast aftermath the ‘fish kill’. Mass mortality of N. thalassina was also suspected because of underwater explosion-a plan that is adopted when complex construction activities were made across the Kuwait Bay sites. Since, fish with swim bladder is susceptible to explosion, environmental variations and hazardous effluents, such factors are validated, and futuristic research delved in this line.